1. Field of the Invention
The present invention relates to the technical field of flat panel display device, and in particular to a method for manufacturing thin-film transistor (TFT) active device and the TFT active device manufactured with the method.
2. The Related Arts
An active matrix flat panel display device has numerous advantages, such as thin device body, less power consumption, and being free of radiation, and is thus widely used. Most of the flat panel display devices available in the market are backlighting liquid crystal displays, which comprise a liquid crystal display panel and a backlight module. The operation principle of the liquid crystal display panel is that liquid crystal molecules are arranged between two parallel glass substrates and electricity is selectively applied to the glass substrates to cause change of the orientation of the liquid crystal molecules in order to refract out the light from a backlight module for formation of an image.
A liquid crystal display panel is composed of a color filter (CF) substrate, a thin-film transistor (TFT) substrate, liquid crystal (LC) interposed between the CF substrate and the TFT substrate, and a sealant. A general manufacturing process comprises a front stage of array process (including thin film, yellow light, etching, and film stripping), an intermediate stage of cell process (including bonding TFT substrate and the CF substrate), and a rear stage of assembling process (including mounting drive ICs and printed circuit board). The front stage of array process generally makes the TFT substrate for controlling the movement of liquid crystal molecules. The intermediate stage of cell process generally introduces liquid crystal between the TFT substrate and the CF substrate. The rear stage of assembling process generally mounts the drive ICs and combining the printed circuit board to effect driving the liquid crystal molecules to rotate for displaying images.
The TFT substrate generally comprises a glass substrate and TFTs formed on the glass substrate. The TFTs are subjected to at least six masking processes before they can be formed on the glass substrate.
Referring to FIGS. 1A-1F, a flow of a conventional manufacture process of a TFT is illustrated. IGZO is an abbreviation standing for indium gallium zinc oxide, which is a technique of oxide thin-film transistor comprising forming a metal oxide active layer on a gate insulation layer of the TFT, this being a TFT driving technique. According to the flow of manufacturing process illustrated in FIGS. 1A-1F, a gate electrode (GE) 101 is first formed on a substrate 100. Next, a gate insulation (GI) layer 102 is formed to cover the gate electrode 101. Then, an oxide semiconductor layer, which is specifically an IGZO layer 103, is formed on the gate insulation layer 101. Then, a first protection layer (an ES layer) 104 is formed on IGZO layer 103. The ES layer is often formed through chemical vapor deposition (CVD) of a precursor substance. Afterwards, a source terminal 105 and a drain terminal 106 are formed of a sputtered metal layer. In addition to the source terminal 105 and the drain terminal 106, the metal layer also serves as wiring lay-out material connecting to the IGZO layer 103. A conventional manufacturing process is to deposit the metal on the IGZO layer 103 and subjects the metal to etching to form the source terminal 105 and the drain terminal 106. The metal used can be copper (Cu), Aluminum (Al), Molybdenum (Mo), titanium (Ti), or a laminated structure thereof. Then, a second protection layer (a PV layer) 107 is formed to cover the source terminal 105 and the drain terminal 106 and is subjected to etching to form a channel. Finally, an indium tin oxide (ITO) layer 108 is formed. To this point, a TFT active device that is generally composed of a gate electrode 101, a gate insulation layer 102, an IGZO layer 103, a first protection layer 104, a source terminal 105, a drain terminal 106, a second protection layer 107, and an ITO layer 108 is formed.